Final answer:
The risk for infection is influenced by the type of microbe, individual immune defenses, environmental conditions, and the presence of other infections or conditions.
Step-by-step explanation:
The four factors that influence the risk for infection are as follows:
- The type of microbe, including its ability to cause harm (its pathogenicity) and its resistance to treatment.
- The immune defenses of the individual, which can be affected by preexisting conditions, environmental factors, and genetic factors.
- Environmental conditions that can alter the effectiveness of sanitation protocols and make it easier for microbes to survive and spread, such as temperature and moisture.
- The presence of other infections or conditions like open sores which can significantly increase the risk of transmission in diseases like HIV.
These factors together can greatly affect an individual's susceptibility to infection and the severity of the disease.